刘基,王丕军,薄海军.内蒙古额济纳旗内乔仑恩格次黑云母二长花岗斑岩中锆石的特征及其指示意义[J].西北地质,2020,53(3):41-55 LIU Ji,WANG Peijun,BO Haijun.Characteristics and Implications of Zircon in Qiaolun'en'geci Biotite Monzogranite Porphyry in Ejina County, Inner Mongolia[J].Northwestern Geology,2020,53(3):41-55
内蒙古额济纳旗内乔仑恩格次黑云母二长花岗斑岩中锆石的特征及其指示意义
Characteristics and Implications of Zircon in Qiaolun'en'geci Biotite Monzogranite Porphyry in Ejina County, Inner Mongolia
投稿时间:2019-11-04  修订日期:2020-04-03
DOI:10.19751/j.cnki.61-1149/p.2020.03.003
中文关键词:  黑云母二长花岗斑岩;锆石;氧逸度;岩浆水含量;额济纳旗乔仑恩格次
英文关键词:Biotite monzogranite porphyry;zircon;oxygen fugacity;magmatic water content;Qiaolun'en'geci in Ejina County
基金项目:武警黄金指挥部“内蒙古自治区额济纳旗呼仍巴斯克等4幅1:5万区域地质矿产调查”项目(DD2016007802)联合资助
作者单位
刘基 中国地质调查局西安矿产资源调查中心, 陕西 西安 710000
中国地质调查局呼和浩特自然资源综合调查中心, 内蒙古 呼和浩特 010010
中国地质大学地质过程与矿产资源国家重点实验室, 北京 100083 
王丕军 中国地质调查局呼和浩特自然资源综合调查中心, 内蒙古 呼和浩特 010010
中国地质大学地质过程与矿产资源国家重点实验室, 北京 100083 
薄海军 中国地质调查局呼和浩特自然资源综合调查中心, 内蒙古 呼和浩特 010010 
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中文摘要:
      低氧逸度和高岩浆水含量是中酸性岩浆内W元素富集成矿的关键因素。乔仑恩格次黑云母二长花岗斑岩体地处中亚造山带中段北山造山带。近几年,发现微弱的钨矿化,该地区是否具有钨矿的成矿潜力亟需进一步的分析研究。笔者对黑云母二长花岗斑岩中岩浆锆石开展年代学、矿物地球化学的研究,并搜集前人主微量元素的数据共同探讨岩浆结晶温度、氧逸度,最终厘定岩浆内W元素的成矿潜力。结果显示,黑云母二长花岗斑岩体具有较高的Ce4+/Ce3+(均值为98.15)、CeN/CeN*(均值为111.55)、EuN/EuN*(均值为0.50)、Ce/Nd (均值为54.89)值,暗示岩体具有较高的氧逸度(lg(fO2)=-12.03;△FMQ+4.53)。而黑云母二长花岗斑岩具无角闪石斑晶、低的Sr/Y值(18.31~38.05)和(La/Yb)N值(13.59~18.71)及明显Eu负异常(EuN/EuN*=0.74~0.86)特征,表明黑云母二长花岗斑岩体在岩浆结晶早期贫水(w(H2O)<4%)。以上分析显示黑云母二长花岗斑岩体具有高氧逸度、低含水量的特征,故认为乔仑恩格次黑云母二长花岗斑岩体不具有形成大规模钨矿床的潜力。
英文摘要:
      Low oxygen fugacity(fO2) and high magmatic water content are the key factors for tungsten (W) enrichment and mineralization. Qiaolun'en'geci biotite monzogranite porphyry is located in the Beishan orogenic belt of Central Asian Orogenic Belt. Weak mineralization of tungsten (W) has been found recently. Whether this area has the potential of W mineralization is worthy of further research. This paper studied zircon in biotite monzogranite porphyry from aspects of chronology and mineral geochemistry and discussed the magma crystallization temperature, oxygen fugacity. The authors hold that there is the tungsten mineralization potential in magma. The data show that Biotite monzogranite porphyry have a high ratio of Ce4+/Ce3+(averaging 98.15), CeN/CeN* (averaging 111.55),EuN/EuN* (averaging 0.50) and Ce/Nd (averaging 54.89), indicating a high fO2 (lg(fO2)=-12.03;△FMQ+4.53). Furthermore biotite monzogranite porphyry has no amphibolite and low Sr/Y (18.31~38.05) and [La/Yb]N (13.59~18.71),and a strong negative Eu anomaly (EuN/EuN*=0.74~0.86), which indicates that it was water-poor in the early magmatic crystallization (w(H2O)<4%). According to the analysis above, Biotite monzogranite porphyry in Qiaolun'en'geci has the characteristics of high Oxygen fugacity and low water content. Thus, it has no much potential to form a large-scale tungsten (W) deposit.
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